Gulf bourses were dragged lower by petrochemicals companies after agreement was reached among world leaders to restrict carbon emissions following marathon climate-change talks in Durban.
The UAE's markets, which do not have a concentration of heavy industry, were buoyant - with the Dubai Financial Market (DFM) rising the most in a week.
The DFM General Index gained 0.9 per cent to 1,396.97 points, while the Abu Dhabi Securities Exchange General Index rose 0.6 per cent to 2,458.91.
But Saudi Arabia's market was weighed down by decreases in industrial juggernauts such as Saudi Basic Industries Corporation (Sabic), which are expected to feel the effect of new restrictions on carbon emissions. Sabic shares fell 0.5 per cent to 97.25 riyals, dragging the Tadawul All-Share Index down 0.2 per cent to 6,288.11.
Industries Qatar, another Gulf company with significant petrochemical operations, also slumped, with shares falling 0.5 per cent to 134.9 rials. Shares in Kuwait's Boubyan Petrochemical fell 1.7 per cent to 0.55 dinars each.
Analysts said these industries, although energy-intensive, adopt a relatively efficient use of gases rather than relying on flaring. But the uncertainty over how companies would be affected was a concern.
"They're cautious on carbon emissions," said one Gulf banker, who asked not to be identified. "I don't know how fast the impact of that cautiousness will be on those companies and how they conduct their business."
Many of the companies had experienced sustained rises to their share prices, so some profit-taking might also be at work, Mr Lee said.
But there were reasons to be sceptical of the impact of a new agreement on petrochemicals companies and other heavy industry, said Hisham Tuffaha, the director of asset management at Bakheet Investment Bank. "Maybe this will appear, but it definitely won't be in the short term."